From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Test report on Champion spark plugs, comparing racing and production models based on their pre-ignition characteristics.
| Identifier | ExFiles\Box 35\3\ scan 197 | |
| Date | 20th February 1928 guessed | |
| X496 BOUGIES CHAMPION Bougies Course | Froid. | Bougies serie. culot long | culot court | culot long | culot court WON'T PRE IGNITE R8 R10 R3 R12 3/8 R2 R1D A.E.1 R1 R7 A.E.9 R6 Good for burning off T.E.L R5 I3 I2 I4 8V. 8 II WILL PRE-IGNITE.. Chaud. | ||